1. Field of the Invention
This invention relates in general to the manufacture of storage disks used in the computer field, and more particularly to a method and apparatus for providing a low cost contact burnish slider.
2. Description of Related Art
Hard disks are used to store information, typically coded information, utilized for data processing. An advantage of such a disk is that it can provide high-speed random access to data stored thereon. Information may be read from or written to any selected area on the memory surface of such a disk. The reading or writing of data may be performed without having to serially search the full contents of the disk to have access to a selected memory location. Generally, a hard disk is mounted with a disk drive, which includes a motor for rotating the hard disk and an actuator for moving a transducer relative to the surface of the rotating hard disk to provide access to circumferential tracks on the hard disk. A plurality of disks may be mounted on a single spindle in spaced relationship to one another and transducers are provided to interact with opposite planar surfaces of each of the disks.
The disks are typically magnetic disks which includes a magnetic surface for recording information thereon. Moreover, the heads which interact with each of the surfaces are referred to as xe2x80x9cflying heads.xe2x80x9d Thus, the flying heads do not touch the surface of the disk during the rotation of the disk. Instead, the flying heads ride on an air bearing that is created between the slider and the disk. The air bearing prevents wear of either the head or the disk surface by reducing or eliminating contacts as the head and the disk surface experience relative movement. Wear of the disk surface due to contact results in the loss of information stored on the magnetic disk.
Accordingly, in a magnetic recording file, a ceramic slider with a magnetic recording head flies at very close spacings over a magnetic recording disk, e.g., on the order of tens of nanometers. To ensure reliability of the interface between the slider and the disk surface, the magnetic recording disk should be made as smooth and free of asperities as possible to eliminate contact between the ceramic slider flying over the surface of this disk. The absence of contact due to asperities on magnetic disks at the flying height of the data heads is tested by flying specially designed sliders called glide sliders which are sensitive to asperity contact. This test is called a glide test and disks that fail this test cannot be used in the magnetic recording file.
There are a number of steps taken to make the magnetic recording disk smooth. One step is to put the layers of the magnetic media on a smooth mechanically polished disk substrate of glass, aluminum with a plated nickel phosphorous layer or some other materials that can be polished to a smooth finish. A smooth finish provides a disk with relatively few asperities, but additional processes to eliminate all asperities up to the flying height of the data heads are necessary to ensure the reliability of the slider/disk interface. These additional steps have traditionally been called disk burnishing.
One such step is slider burnish. In contrast to sliders forming the data heads in a typical disk drive, burnish sliders are designed to fly at flying heights lower than the data heads in the magnetic recording files and must have surfaces that can cut or abrade asperities. Burnish sliders have significant asperity contact and therefore have to fly at stable, low flying heights even when their air-bearing surfaces have wear on pad surfaces and edges.
The basic problem for burnish sliders is to remain in contact or at the initial low flying heights even as the pad surfaces and leading edges wear. As various air-bearing surfaces wear, the air-bearing surfaces build up an effective taper that can change the flying height of the burnish slider and render it ineffective at burnishing asperities of the disk surface. The consequence of inefficient slider burnish is that disks have asperities remaining that are detected at glide test and are rejected. In addition smaller asperities that pass glide may remain on the disk and reduce the overall reliability of the files in which these disks are used.
It can be seen that there is a need for a burnish slider that can remain in contact or at the initial low flying heights even as the pad surfaces and leading edges wear.
To overcome the limitations in the prior art described above, and to overcome other limitations that will become apparent upon reading and understanding the present specification, the present invention discloses a method and apparatus for providing a low cost contact burnish slider.
The present invention solves the above-described problems by providing a burnish slider that can remain in contact or at the initial low flying heights even as the pad surfaces and leading edges wear.
A system in accordance with the principles of the present invention includes a body having a leading edge and a trailing edge and an air bearing surface being configured at the leading edge of the body to cut disk asperities as the slider flies and configured away from the leading edge to maintain a flying attitude wherein the leading edge is near the data recording surface and to provide restoring forces to maintain the flying attitude.
Other embodiments of a system in accordance with the principles of the invention may include alternative or optional additional aspects. One such aspect of the present invention is that the air bearing surface includes a front pad proximal to the leading edge and a rear pad distal to the leading edge. Alternatively, the air bearing surface may include two front pads proximal to the leading edge on opposite sides of the body and two rear pads distal to the leading edge and disposed on opposite sides of the body.
Another aspect of the present invention is that the front and rear pad(s) extends substantially across the body of the slider.
Another aspect of the present invention is that the front pad(s) includes a small area for exerting a small air bearing force relative to a suspension load and an air bearing force created by the rear pad(s).
Another aspect of the present invention is that the rear pad(s) has an air bearing surface substantially greater than the front pad(s).
Another aspect of the present invention is that the rear pad(s) extends substantially from a midpoint of the body to the trailing edge.
Another aspect of the present invention is that an offset pivot is provided for constraining the moment balance of the slider to provide a low pitch flying attitude.
Another aspect of the present invention is that the rear pad(s) further includes a mechanical taper proximal to the trailing edge to minimize load/unload damage.
Another aspect of the present invention is that the air bearing surface configuration away from the leading edge provides a force that restores the flying attitude to the slider when an impulse lifting the leading edge is encountered.
Another aspect of the present invention is that the front pads have a width and the rear pads have a width, the width of the front and rear pads being substantially equal.
These and various other advantages and features of novelty which characterize the invention are pointed out with particularity in the claims annexed hereto and form a part hereof. However, for a better understanding of the invention, its advantages, and the objects obtained by its use, reference should be made to the drawings which form a further part hereof, and to accompanying descriptive matter, in which there are illustrated and described specific examples of an apparatus in accordance with the invention.